The stock market lost ground on Thursday, pushed lower by worries about the future course of U.S. interest rates and worldwide economic growth. Volatility in major indexes continued, with gains in the morning giving way to deep losses that largely eased up toward the end of the session. Yet some stocks had bad news that prevented them from avoiding substantial share-price declines. Square (SQ 0.37%), Wayfair (W -0.10%), and CannTrust Holdings (CNTTQ) were among the worst performers. Here's why they did so poorly.

Square's outlook raises growth questions

Shares of Square fell 8% after the payment processor reported its first-quarter financial results. The company said that revenue jumped 43% compared to the year-earlier figure, with gross payment volume rising 27% to $22.6 billion. Square posted a modest net loss, but what really seemed to cause shareholders to lose confidence was the company's decision to leave earnings guidance for the full year unchanged despite boosting sales projections. Even with the decline, bullish investors still think that Square's key growth drivers, including its fast-growing Cash App and the new Square Capital lending service, have the potential to keep making the company an increasingly important part of the fintech sector -- especially for small businesses who rely on its services.

Square logo of concentric black and white squares.

Image source: Square.

Wayfair tests investors' patience

Wayfair's stock dropped 7% following the e-commerce-focused home furnishings retailer's release of its first-quarter financial report. Wayfair reported strong top-line growth of 39%, with direct-to-consumer sales matching that growth rate and even better performance in its international sales. However, Wayfair's net losses widened by more than 75% on a per-share basis, as the furniture specialist spent more on advertising and overhead expenses than it has in the past. Investors seem dubious about the prudence of that spending, but as long as it can keep bringing in new customers and eventually boost their ordering to the point at which it becomes profitable, then it'll have been money well spent for Wayfair.

CannTrust's cash raise is a bummer

Finally, shares of CannTrust Holdings dropped 13%. The Canadian cannabis company priced a previously announced secondary offering of stock this morning, but demand among investors was so weak that it had to cut its price by more than 15% compared to where the shares closed on Wednesday night to get the deal done. In the end, CannTrust sold 30.9 million shares at $5.50 per share, with current shareholders adding another 5.45 million shares to the sale. Although that'll give the marijuana company about $170 million to use toward expanding capacity, it comes at the cost of dilution for CannTrust's current shareholders.